Enable assertions in release builds

This replaces the `assert` function by `syntaxAssert`, which also checks the condition in release builds.

Always enabling assertions regresses parsing time of MovieSwiftUI by 12%. I think that’s a price we should be willing to pay to get the additional safety these assertions are giving us.

Alternatively, we could consider
- Offering a conditional compilation flag to only enable assertions in Release+Assert builds, similar to what we do in the C++ parser
- Offering a conditional compilation flag to explicitly disable assertions in cases where performance is of the uttermost importance – I can’t think of any right now.

Enabling `RawSyntaxValidation` decreases parsing time by another 40%. That seems a little bit too much to me.

Author: ahoppen

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftparser/ParserEntryFile.swift

@@ -84,7 +84,7 @@ let parserEntryFile = SourceFileSyntax {
       """
       mutating func parseRemainder<R: RawSyntaxNodeProtocol>(into: R) -> R {
         guard !into.raw.kind.isSyntaxCollection, let layout = into.raw.layoutView else {
-          assertionFailure("Only support parsing of non-collection layout nodes")
+          syntaxAssertionFailure("Only support parsing of non-collection layout nodes")
           return into
         }
 

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/RawSyntaxNodesFile.swift

@@ -129,7 +129,7 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: "\(generateCopyrightHea
       DeclSyntax(
         """
         init(raw: RawSyntax) {
-          assert(Self.isKindOf(raw))
+          syntaxAssert(Self.isKindOf(raw))
           self.raw = raw
         }
         """

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxCollectionsFile.swift

@@ -158,7 +158,7 @@ let syntaxCollectionsFile = SourceFileSyntax(leadingTrivia: [.blockComment(gener
         /// that the `SyntaxData` is of the correct kind. If it is not, the behaviour
         /// is undefined.
         internal init(_ data: SyntaxData) {
-          assert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
+          syntaxAssert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
           self._syntaxNode = Syntax(data)
         }
         """

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxNodeFile.swift

@@ -59,7 +59,7 @@ func syntaxNode(emitKind: String) -> SourceFileSyntax {
           /// that the `SyntaxData` is of the correct kind. If it is not, the behaviour
           /// is undefined.
           internal init(_ data: SyntaxData) {
-            assert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
+            syntaxAssert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
             self._syntaxNode = Syntax(data)
           }
           """

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxRewriterFile.swift

@@ -321,7 +321,7 @@ let syntaxRewriterFile = SourceFileSyntax(leadingTrivia: .docLineComment(generat
           // A child node was rewritten. Build the updated node.
           
           // Sanity check, ensure the new children are the same length.
-          assert(newLayout.count == node.raw.layoutView!.children.count)
+          syntaxAssert(newLayout.count == node.raw.layoutView!.children.count)
           
           let arena = SyntaxArena()
           let newRaw = node.raw.layoutView!.replacingLayout(with: Array(newLayout), arena: arena)

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/TokenKindFile.swift

@@ -282,7 +282,7 @@ let tokenKindFile = SourceFileSyntax {
             }
           } else if token.text != nil {
             SwitchCaseSyntax("case .\(raw: token.swiftKind):") {
-              ExprSyntax("assert(text.isEmpty || rawKind.defaultText.map(String.init) == text)")
+              ExprSyntax("syntaxAssert(text.isEmpty || rawKind.defaultText.map(String.init) == text)")
               StmtSyntax("return .\(raw: token.swiftKind)")
             }
           } else {

Sources/SwiftDiagnostics/Diagnostic.swift

@@ -80,7 +80,7 @@ public struct DiagnosticsError: Error {
   public init(diagnostics: [Diagnostic]) {
     self.diagnostics = diagnostics
 
-    assert(
+    syntaxAssert(
       diagnostics.contains(where: { $0.diagMessage.severity == .error }),
       "at least one diagnostic must have severity == .error"
     )

Sources/SwiftDiagnostics/FixIt.swift

@@ -57,7 +57,7 @@ public struct FixIt {
   public let changes: Changes
 
   public init(message: FixItMessage, changes: Changes) {
-    assert(!changes.changes.isEmpty, "A Fix-It must have at least one change associated with it")
+    syntaxAssert(!changes.changes.isEmpty, "A Fix-It must have at least one change associated with it")
     self.message = message
     self.changes = changes
   }

Sources/SwiftParser/Declarations.swift

@@ -458,7 +458,7 @@ extension Parser {
       )
     }
 
-    assert(self.currentToken.starts(with: "<"))
+    syntaxAssert(self.currentToken.starts(with: "<"))
     let langle = self.consumeAnyToken(remapping: .leftAngle)
     var elements = [RawGenericParameterSyntax]()
     do {

Sources/SwiftParser/Expressions.swift

@@ -192,7 +192,7 @@ extension Parser {
       return lastElement
     }
 
-    assert(
+    syntaxAssert(
       elements.count.isMultiple(of: 2),
       "elements must have a even number of elements"
     )
@@ -591,7 +591,7 @@ extension Parser {
     declNameArgs: RawDeclNameArgumentsSyntax?,
     generics: RawGenericArgumentClauseSyntax?
   ) {
-    assert(self.at(.period))
+    syntaxAssert(self.at(.period))
     let (unexpectedPeriod, period, skipMemberName) = self.consumeMemberPeriod(previousNode: previousNode)
     if skipMemberName {
       let missingIdentifier = missingToken(.identifier)
@@ -657,7 +657,7 @@ extension Parser {
     _ flavor: ExprFlavor,
     forDirective: Bool
   ) -> RawExprSyntax {
-    assert(self.at(.poundIfKeyword))
+    syntaxAssert(self.at(.poundIfKeyword))
 
     let config = self.parsePoundIfDirective { parser -> RawExprSyntax? in
       let head: RawExprSyntax
@@ -947,7 +947,7 @@ extension Parser {
       if self.currentToken.starts(with: "!") {
         questionOrExclaim = self.consumePrefix("!", as: .exclamationMark)
       } else {
-        assert(self.currentToken.starts(with: "?"))
+        syntaxAssert(self.currentToken.starts(with: "?"))
         questionOrExclaim = self.consumePrefix("?", as: .postfixQuestionMark)
       }
 
@@ -1013,7 +1013,7 @@ extension Parser {
           period = nil
         }
 
-        assert(self.at(.leftSquareBracket))
+        syntaxAssert(self.at(.leftSquareBracket))
         let lsquare = self.consumeAnyToken()
         let args: [RawTupleExprElementSyntax]
         if self.at(.rightSquareBracket) {
@@ -2054,7 +2054,7 @@ extension Parser.Lookahead {
   /// handle this by doing some lookahead in common situations. And later, Sema
   /// will emit a diagnostic with a fixit to add wrapping parens.
   mutating func isValidTrailingClosure(_ flavor: Parser.ExprFlavor) -> Bool {
-    assert(self.at(.leftBrace), "Couldn't be a trailing closure")
+    syntaxAssert(self.at(.leftBrace), "Couldn't be a trailing closure")
 
     // If this is the start of a get/set accessor, then it isn't a trailing
     // closure.
@@ -2239,7 +2239,7 @@ extension Parser {
               { $0.parseSwitchCases(allowStandaloneStmtRecovery: allowStandaloneStmtRecovery) },
               syntax: { parser, cases in
                 guard cases.count == 1, let firstCase = cases.first else {
-                  assert(cases.isEmpty)
+                  syntaxAssert(cases.isEmpty)
                   return .switchCases(RawSwitchCaseListSyntax(elements: [], arena: parser.arena))
                 }
                 return .switchCases(firstCase)